Research On Defect Detection Of Crude Oil Storage Tank Based On Acoustic Emission Technology

Due to the increasing demand of oil consumption,China’s crude oil storage tanks have been developing into large scale,which is accompanied by the increasingly serious safety problems of long-term service tanks.Once the oil spill,fire explosion and other safety accidents occur,the consequences are unimaginable.The Huangdao oil Depot has 38 crude oil storage tanks with total reserves of 2.1 million cubic meters,all of which were built in the late1990 s and early 2000 s and have been in service for nearly 20 years or more.The operation plan of Huangdao oil depot requires that at least three tanks need to be stopped for maintenance every year.Due to the tight production task,many tanks are in extended service to varying degrees.Therefore,it is necessary to carry out scientific analysis on the storage tank arranged for overhaul to ensure the maximum benefit of the enterprise.Taking acoustic emission technology as the research object,this paper conducts online detection research on the defects of crude oil storage tanks by establishing the sound source identification algorithm and sound source location model.By analyzing and processing the experimental data,the author puts forward the evaluation standard of tank defects and the tank bottom failure model,and verifies the reliability of the proposed theoretical model by carrying out on-site acoustic emission detection and tank opening verification of the tank in service.Firstly,the author analyzed the characteristics of acoustic emission signals of crude oil storage tank defects,and identified that the sound source signals of crude oil storage tank defects were mainly burst type.According to the characteristics of burst type signals,an acoustic emission signal identification algorithm based on fuzzy C-means clustering was proposed for crude oil storage tank defects.Simulation experiments showed that the algorithm could accurately identify the acoustic emission signals of crude oil storage tank defects and solve the problem of classification when the same sound source reaches different sensors.The author established acoustic emission location model of crude oil storage tank defects based on the time difference location method.According to the number of sound source impacts and location events,the evaluation criteria for the defect of crude oil storage tank were proposed,the corrosion degree of storage tank was defined.And the effectiveness of the defect location method was verified by the lead break simulation experiment.The reliability of positioning method and defect evaluation standard is proved by acoustic emission test and tank opening verification.By analyzing and processing the data collected in the process of acoustic emission detection,the author established the tank bottom failure model,and calculated and analyzed the relationship between the impact number of the defective sound source and the corrosion depth through the linear regression equation.The author predicted the corrosion depth of tank bottom in service,and verified that the failure model of tank bottom conforms to the actual situation of production by detecting the corrosion of tank bottom in the field,which is helpful for the dynamic scientific management of tank.At the same time,it can create conditions for enterprises to inspect and repair storage tanks.Under the condition of ensuring normal production and operation,it can further control operating costs such as testing and maintenance,further check and eliminate hidden dangers,give full play to economic benefits,and maintain the essential safety of equipment.